Natural equivalent of chemically modified starch

ABSTRACT

The present invention relates to a composition comprising citrus fruit fiber having a water binding capacity of from 8 to 25 (w/w) and native starch selected from the group consisting of corn starch, rice flour, sorghum starch, tapioca starch and mixture thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application under 35 U.S.C. § 371and claims benefit of International Application No. PCT/EP2007/062739having an International Filing Date of Nov. 23, 2007, which claims thebenefit of priority of EP 06124634.4 having a filing date of Nov. 23,2006.

TECHNICAL FIELD

The current invention relates to an edible substitute for chemicallymodified starch. It further relates to a process for preparing saidsubstitute which comprises citrus fibers and native starch. Finally, thepresent invention pertains to the use of citrus fiber and native starchas a natural alternative to chemically modified starch.

BACKGROUND OF THE INVENTION

Food manufacturers are continuously challenged to find ways to presentan appetizing and authentic food product at minimized raw materialcosts. One area of particular endeavor has been the goal of producingcompositions including fully natural ingredients. Particularly, theconsumer demands for foods containing starches which have not beenchemically modified but which have the same functional properties aschemically modified starches.

Indeed, starches are often chemically modified with different reagentsto produce starches having, for example, excellent tolerance toprocessing variables such as heat, shear, pH extremes, and storagestability. Such chemically modified starches provide interalia adesirable smooth texture and possess viscosity stability throughout theprocessing operation and normal shelf life of the food. In contrast,unmodified starches breakdown in viscosity, loose thickening capacityand textural qualities, and behave unpredictably during storage as aresult of the stresses encountered during food processing. Heat, shear,and/or an extreme pH, especially an acidic pH, tend to fully disrupt thestarch granules and disperse the starch polymers into the food. Hence,unmodified starches also called native starches are generally unsuitablefor use in processed foods.

Different solutions have already been proposed in the art to addressthis issue, for example, in EP 721 471 and EP 1 038 882 thermallyinhibited starches and flours that are functionally equivalent tochemically modified (i.e., crosslinked) starches are disclosed.

EP 830 379 and 1 159 880 relate to pregelatinized non-granular starchesthat are inhibited in order to have the textural properties ofchemically crosslinked pregelatinized non-granular starches. In thesereferences, the “physically” modified starches described do not containchemical modifications but their structure is modified during theprocess.

Another solution that has been proposed in the art is to fully replacechemically modified starch by citrus fiber in low fat emulsions. Thissolution seems to be satisfactory, even if some grittiness appears, ascitrus fiber is a highly functional texturizing material but citrusfiber suffers from being relatively expensive.

Accordingly, there is still a need for having a low cost naturalingredient exhibiting the same functionality than chemically modifiedstarch. The present invention fulfills this need by providing acomposition comprising citrus fiber and native starch, its use as ediblesubstitute for chemically modified starch, and a process for preparingit. Indeed, the inventors have surprisingly found that mixing citrusfiber with native starch results in a product having process tolerancerequired in the food industry, such as resistance to shear, as well asimproved texture, and freeze thaw stability.

SUMMARY OF THE INVENTION

The current invention relates to a composition suitable to substitutechemically modified starch comprising citrus fiber having a waterbinding capacity of from 7 to 25 (w/w) and native starch selected fromthe group consisting of corn starch, rice flour, sorghum starch, tapiocastarch, waxy wheat flour, amylase free potato starch and mixturethereof. In a preferred embodiment, the starch used is a waxy starch.

Also part of this invention is a composition where the ratio of citrusfruit fiber to native starch is from about 1:10 to about 2:1.

The citrus fiber, in the present invention, is having a total dietaryfiber content of from 60 to 85-wt % (dry weight) and a water bindingcapacity of from 7 to 25 (w/w). The citrus fiber can comprise up to 12%(w/w) proteins. Furthermore the citrus fiber is obtainable from citrusfruit selected from the group consisting of oranges, tangerines, limes,lemons and grapefruit. In a preferred embodiment the citrus fiber usedis orange pulp fiber.

The composition according to the invention may further comprise edibleadditives and for example xanthan gum, guar gum, pectin, carrageenan,fiber, soy protein and mixtures thereof.

The present invention also relates to a process for preparing thecomposition of the present invention where a blend of citrus fiber andnative starch is prepared and then treated mechanically in order tohomogenized the blend to form a mixture; after that the mixture iscooked up to the gelatinization temperature of the starch understirring.

The currently disclosed invention is suitable to be used in foodapplications, feed applications, pharma products or cosmetics. Saucesand soups containing the composition of the present invention arepreferred embodiments. The amount of the composition according to thepresent invention in the final product is preferably from about 2 toabout 6 percent by weight.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a comparative example of the behaviors of a chemicallymodified starch (C*Tex 06209), a thermally inhibited starch (Novation2300) and a composition according to the invention (citrus fiber andnative starch) when measured in rotational mode.

DETAILED DESCRIPTION

The current invention relates to a composition suitable to substitutechemically modified starch comprising citrus fiber having a waterbinding capacity of from 7 to 25 (w/w) and native starch selected fromthe group consisting of corn starch, glutinous rice flour, sorghumstarch, tapioca starch, waxy wheat flour, amylase free potato starch andmixture thereof. In a preferred embodiment, the native starch is a waxystarch and particularly glutinous rice flour.

The citrus fiber, used in the present invention, is a valuable componenthaving relatively high total dietary fiber content and a balanced ratioof soluble to insoluble dietary fiber. For example, the total dietaryfiber preferably is made up of about 45-50% soluble dietary fiber andfrom 50-55% insoluble dietary fiber. The balanced dietary fiber spectruminsoluble (structural) and soluble (chiefly pectin) fiber isadvantageous in physiological functionality over cereal-based fibers.Citrus fiber, particularly orange fiber, more in particular dried citrusfiber; has an extremely high water binding capacity, resulting in highviscosities compared to other citrus fibers such as Vitacel™ orangefiber (available from Rettenmaier). In one preferred embodiment, driedcitrus fiber has a total dietary content of from about 60 to about 85-wt% (based on dry substance) and a water binding capacity from 7 to about25 (w/w). Preferably the total dietary fiber content is at least about70-wt % and the water binding capacity is at least about 8 (w/w), morepreferably at least about 12, most preferably from 19 to 25. The proteincontent of the dried citrus fiber is up to 12, preferably from 8 to12-wt %.

The citrus fiber is extracted from citrus vesicles from a wide varietyof citrus fruits, non-limiting examples of which include oranges,tangerines, limes, lemons, and grapefruit.

Citrus vesicles refer to the cellulosic material contained in the inner,juice-containing portion of citrus fruit. Citrus vesicles are sometimesalso referred to as coarse pulp, floaters, citrus cells, floating pulp,or pulp. In contrast, citrus flour obtained from citrus peel ischaracterized by an orange peel taste and odor, and a dark orange color,which is severely limiting the product's uses. Additional advantages ofcitrus fiber versus citrus flour are a higher total dietary fibercontent (e.g., about 72-wt % versus 58-wt %); lower carbohydrate content(e.g., about 5-wt % versus 15-wt %); and higher water binding (e.g.,greater than about 8.5 grams of water per gram of fiber versus 5.5 g/g).

The ratio soluble to insoluble dietary fiber is an important factor inthe citrus fiber's functionality. Other important considerations includethe degree of milling (granulometry) and drying conditions (process ofdrying). Generally, a higher degree of milling (i.e., a finer fibergranulometry) results in more smoothness of the fiber in the solution,as well as reduced water absorption capacity and reduced oil bindingcapacity compared to coarse fibers. Preferably dried citrus fruit fiberis obtainable according to the process disclosed in the pending patentapplication WO 2006/033697. In a preferred embodiment, the citrus fiberis orange fiber having a water binding capacity of from 12 to 25,preferably from 19 to 25. Said orange fiber has preferably an oilbinding capacity of from 2 to 10, preferably from 4 to 10, morepreferably from 5 to 9.

Without being bound by any theory, it is believed, according to thepresent invention, that the citrus fiber when included in the presentinventive combination and then further processed is acting as aprotective agent for the starch. Indeed, the resistance of said starchis increased, particularly when treated with shear forces. It isbelieved that this higher resistance is due to starch granule swellinginhibition allowed by the citrus fiber. According to the presentinvention, the more the fiber binds water and oil the more the starchwill be protected by said fiber.

A preferred version of the invention involves an orange fiber having awater binding capacity of 19 to 25, an oil binding capacity of from 5 to9 in combination with glutinous rice flour.

Also part of this invention is a composition where the weight ratio ofcitrus fruit fiber to native starch is from about 1:10 to about 2:1,preferably from 1:7 to 1:1, more preferably from 1.5 to 1:3.6, and mostpreferably from 1:5 to 1:2.

Said composition can further comprise edible additives. These edibleadditives are selected from the group consisting of carbohydrates, gums,proteins, peptides, amino acids, pectins, antioxidants, trace elements,electrolytes, intense sweeteners, edible acids, flavors, barleybeta-glucans, colorants, preservatives, and mixtures thereof.

The carbohydrates are selected from the group consisting ofmonosaccharides, disaccharides, oligosaccharides, dextrins, fibers,starch hydrolysates, polyols and mixtures thereof. The monosaccharidesinclude tetroses, pentoses, hexoses and ketohexoses.

Typical disaccharides include sucrose, maltose, trehalulose, melibiose,kojibiose, sophorose, laminaribiose, isomaltose, gentiobiose,cellobiose, mannobiose, lactose, leucrose, maltulose, turanose and thelike.

Starch hydrolysates are produced by the controlled acid or enzymatichydrolysis of starch and can be subdivided into two specific categories,maltodextrins and glucose syrups and are characterized by DE number(dextrose equivalent). In fact, DE number is a measurement of thepercentage of reducing sugars present in the syrup and calculated asdextrose on a dry weight basis. Maltodextrins have a DE (dextroseequivalent) number up to 20 whereas glucose syrups have an DE numbergreater than 20.

Dextrins are prepared according to the dextrinisation method.Dextrinisation is a heat treatment of dry starch in presence or absenceof acid.

The low-calorie fibers can be polydextrose, arabinogalactan, chitosan,chitin, xanthan, pectin, cellulosics, konjac, gum Arabic, soy fiber,inulin, hydrolysed guar, guar gum, beta-glucan, carageenan, locust beangum, alginate, polyglycol alginate.

Among the major physiological electrolytes are sodium, potassium,chloride, calcium, and magnesium. Further trace elements can be includedsuch as chromium, copper, selenium, iron, manganese, molybdenum, zincand mixtures thereof.

The edible acids can be selected from phosphoric acid, citric acid,malic acid, succinic acid, adipic acid, gluconic acid, tartaric acid,fumaric acid and mixtures thereof.

An intense sweetener, which can be used as non-nutritive sweetener canbe selected from the group consisting of aspartame, acesulfame saltssuch as acesulfame-K, saccharins (e.g. sodium and calcium salts),cyclamates (e.g. sodium and calcium salts), sucralose, alitame, neotame,steviosides, glycyrrhizin, neohesperidin dihydrochalcone, monatin,monellin, thaumatin, brazzein and mixtures thereof.

The flavors are selected from fruit flavors, botanical flavors andmixtures thereof. Preferred flavors are cola flavor, grape flavor,cherry flavor, apple flavor and citrus flavors such as orange flavor,lemon flavor, lime flavor, fruit punch and mixtures thereof. The amountof flavor depends upon the flavor or flavors selected, the flavorimpression desired and the form of flavor used.

If desired, coloring agents can also be added. Any coloring agentapproved for food use can be utilized for the current invention.

When desired, preservatives such as potassium sorbate and sodiumbenzoate can be added.

In a preferred embodiment, the edible additive added is selected fromthe group consisting of xanthan gum, guar gum, pectin, carrageenan,fiber, soy protein and mixture thereof. In another embodiment, thepreferred edible additive is xanthan gum.

The present invention also encompasses a process for preparing acomposition comprising citrus fiber having a water binding capacity offrom 7 to 25 (w/w) and native starch selected from the group consistingof corn starch, rice flour, sorghum starch, tapioca starch and mixturethereof.

Said process comprising the steps of:

-   -   a) Blending citrus fruit fibers and native starch,    -   b) Treating mechanically the blend of step a) to obtain a        homogeneous mixture,    -   c) Cooking the mixture under gentle stirring up to the        gelatinization temperature of the starch.

To form the blend of step a, any homogenization method can be used asthe degree of hydration of the citrus fruit fiber is not highlycritical.

Suitable mechanical treatment for step b) is treatment with high-shearmixers, high-pressure valve homogenization, microfluidisation,high-power ultrasound and the like. By applying a strong shearing force,such as for example a high-pressure valve homogenizer, less dense fibreparticles and increased thickening can be obtained.

The mixture of step b) is then cooked to swell the starch granules. Thiswill render the medium viscous; gentle stirring is used in order tohomogenize the mixture, strong mechanical treatment should be avoided tonot disrupt the starch granules.

The gelatinization temperature depends on the type of starch used; thisshould be determined by the skilled person; however gelatinization forsome type of native starch can be found in the literature and forexample in the book by David J. Thomas and Williams A. Atwell, Starches,Eagan Press Handbook Series, American Association of Cereal Chemists,St. Paul, Minn. (1999), pages 25-30.

Cited temperatures are as follow:

Starch source Gelatinization temperature (° C.) Wheat 52-85 Tapioca52-65 Waxy Corn 63-72

The gelatinization temperature are given by ranges as it depends on themoisture content and the salt content of the medium.

The current invention relates to the use of the currently disclosedcomposition in food applications, feed applications, pharma products orcosmetics. Food applications may include beverages, dairy products, icecreams, sorbets and, desserts. Said beverages include concentrates,gels, energy drinks, and carbonated beverages, non-carbonated beverages,syrups. The beverage can be any medical syrup or any drinkable solutionincluding iced tea, and fruit juices, vegetable based juices, lemonades,cordials, nut based drinks, cocoa based drinks, dairy products such asmilk, whey, yogurts, buttermilk and drinks based on them. Beverageconcentrate refers to a concentrate that is in liquid form. The liquidconcentrate can be in the form of a relatively thick, syrupy liquid.Preferred application are soups, dressing, bakery products, low fatspreads and sauces. More preferred applications are béchamel sauces andtomato sauces.

The combination of the present invention is also suitable to be includedin hot instant product like soups; in this case, the skilled person mustenvisage other kind of starches. Indeed, if the mixture has not beencooked before being included in the instant product, the consumer willhave to face textural problem like sandiness. Thus to overcome this,pregelatinized starch e.g. spray cooked starch must be used.

Another possibility is to combine the citrus fiber with thermallyinhibited starch for application to be submitted to extreme conditions(for example pH around 3.5 and temperature above 95° C.) or forapplication requiring extremely high viscosity.

In a preferred embodiment the combination according to the presentinvention is present in the final product in an amount of from about 1.5to about 7-wt % of the composition, preferably from 2 to 6-wt %, andmore preferably from 3 to 5-wt %.

The current invention has the following advantages:

-   -   1) The composition, comprising citrus fruit fiber and native        starch, has a high nutritional value, is stable during the        process and, allows positive food labeling.    -   2) Using native starch, which is a very cheap ingredient,        permits to manufacture a low cost, highly efficient, and natural        texturizing agent.    -   3) This composition is also useful for products requesting cold        storage as the protective effect of the citrus fiber helps the        stabilization of the starch even at low temperature.

The invention is further defined by reference to the following examplesdescribing in detail the preparation of the composition of the presentinvention. The invention described and claimed herein is not to belimited in scope by the specific embodiments herein disclosed, sincethese embodiments are intended as illustrations of several aspects ofthe invention. Any equivalent embodiments are intended to be within thescope of this invention. Indeed, various modifications of the inventionin addition to those shown and described herein will become apparent tothose skilled in the art from the foregoing description. Suchmodifications are also intended to fall within the scope of the appendedclaims.

EXAMPLE Example 1 Water and Oil Binding Capacity Analysis

The water binding (measured according to Protocol I) and oil bindingcapacity (measured according Protocol II) of orange pulp fiber (OPF)obtained by the process disclosed in WO2006/033697 were measured. Theresult were as follow:

WATER BINDNG OIL BINDING CAPACITY CAPACITY SAMPLES g water/g product gwater/g product OPF 40 μm 19 5 OPF 75 μm 19 5 OPF 250 μm 24 9.5

As apparent the granulometry has an influence on both the water bindingcapacity and the oil binding capacity of the products. This experimentshows that depending on the result to be achieved, the skilled personcould have to monitor the granulometry in order to bring more or lessprotective effect to the starch.

Example 2 Resistance of the Invention to Process Parameters (ShearTreatment)

A composition of orange pulp fiber and waxy cornstarch on one side andOrange pulp fiber (OPF) and cornstarch on the other side was formed andsubmitted to shear treatment. The shear treatment applied was 13500 rpmwith Silverson mixer during 1.5 minute.

All the viscosity measurements have been made using a Brookfield with acylindrical spindle (62) at 10 rpm during 20 seconds.

The results are apparent in the following table:

Before treatment After treatment Material (mPA · s) (mPa · s) Cornstarch(2.5%) + 116 000  105 000  OPF (4%) Cornstarch (4%) + 76 300 69 200 OPF(2.5%) Waxy cornstarch (2.5%) + 78 100 73 200 OPF (4%) Waxy cornstarch(4%) + 55 300 51 200 OPF (2.5%)

As apparent the combination of the invention is shear resistant as itsvalues before and after treatment are almost the same.

Example 3 Preparation of a Sauce

Three sauces were prepared with the following recipe:

Ingredients Weight (g) Composition (w % as is) Sunflower oil 75 10.0Skimmed milk powder 30 4.0 Egg yolk powder 11 1.5 Thickeners* 22.5 3.0Salt 3 0.4 Demi-water 608 81.1 TOTAL 750 100.0 *The thickeners testedwere: the composition according to the invention: glutinous rice flourand Orange pulp fiber (ratio 3:1) a thermally inhibited stach: NOVATION2300 a chemically modified starch: C*Tex 06209

The rheology of the different sauces was measured at 60° C.(rotation=FIG. 1).

As apparent from FIG. 1, the combination according to the invention isas good as thermally inhibited starch that is used to replace chemicallymodified starch.

Another trial has been made with 3% native starch and 1% orange pulpfiber. In this case, the natural substitute can even compete withchemically modified starch per se.

Example 4 Descriptive Textural and Sensory Analysis of the Sauces afterCold Storage (5° C.)

Descriptive textural and sensory analysis of the sauces after coldstorage (5° C.).

It was not possible to measure the syneresis for C*Tex 06209, Novation2300, and glutinous rice flour/orange pulp fiber as all were below thedetection limit.

Thus visual observation was used, the result can be found in thefollowing table:

Water Bulk Overall rating syneresis Fat syneresis appearance (scale −1to +1) Good scores Glutinous rice No syneresis No syneresis Short,creamy 0.7 flour/orange pulp fiber Medium scores C*Tex 06209 Nosyneresis Little Short, grainy 0.3 Bad scores Novation 2300 No syneresisFat globule Long −0.3 on surface

When manufacturing sauces, one of the targets is to obtain a productwhich are short, creamy mouthfeel, and not being subject to syneresisfor appearance and shelf-life stability.

As apparent from the table here above, the only product in thecomparative example having the required features was the saucecontaining the inventive combination.

Protocol I

Water Binding Capacity

3 samples were ground at different granulometry (40 μm, 75 μm, and, 250μm) and then weighted with a precision balance Sartorius CP 3245. Eachsample was prepared in double and an average was made to give the finalresult.

The procedure was as follow:

-   -   In a 50 ml centrifuge tube, 0.5 g of the fiber (dry powder) was        weighted (W1),    -   40 g milli-Q water was added. The weight of the water was noted        (W2),    -   The tube was closed and stirred during 1 min by hand,    -   The tube was then submitted to a centrifugation during 5 min at        2000 rpm with the centrifuge Labofuge 400 Heraeus,    -   The supernatant was decanted and weighted (W3).

The water binding capacity (WBC) is expressed as g water/g sample:WBC=(W2−W3)/W1Protocol IIOil Binding Capacity

The oil binding (OLB) of a product was determined by centrifugering a 5%powder dispersion and weighing the precipitate.

2 (independant) product dispersions were prepared by dispersing 2.5 gpowder (W1) in 50 g (W2) soya-oil (standard quality) in a 300 ml beaker.

The samples were stirred for 10 minutes at about 500 rpm until theproduct was completely dispersed.

The samples were then left 30 minutes until the samples were adapted tothe hydrophobicity.

The dispersions were stirred and for each sample a centrifuge tube withapproximately 45 g product-in-oil dispersion was filled. The weight ofthe tube was noted as W3 and the total weight after filling thecentrifuge tube with the dispersion was W4.

The tubes were centrifuged during 5 min at 3800 rpm with a SorvallAutomatic centrifuge SS-3. The supernatants were then decanted and thecentrifuged tubes containing the precipitate were weighed again (W5).

The oil-binding capacity is expressed as g oil/g sample:OLB=Wco/Wcp

% product in start oil mixture Wp = W1 × 100/(W1 + W2) % oil in startoil mixture Wo = W2 × 100/(W1 + W2) Product weight Wcp = (Wp/100) × (W4− W3) Oil bind Wco = W5 − W3 − Wcp

The invention claimed is:
 1. A process for preparing a compositioncomprising the steps of: a) making a mixture consisting of citrus fruitfibers and native starch at a weight ratio of citrus fruit fiber tonative starch of 1:5 to 1:2, wherein the citrus fruit fiber is fiberextracted from citrus vesicles which has a water-binding capacity of 7to 25 grams of water per gram of fiber and a total dietary fiber contentof 60 to 85 wt %, the total dietary fiber consisting of 45 to 50%soluble dietary fiber and 50 to 55% insoluble dietary fiber and whereinthe native starch is selected from the group consisting of corn starch,rice flour, sorghum starch, tapioca starch, waxy wheat flour,amylose-free potato starch and mixtures thereof, b) mechanicallytreating the citrus fruit fiber and the native starch with a high shearforce to obtain a homogeneous mixture, and c) cooking the homogeneousmixture under gentle stirring up to the gelatinization temperature ofthe starch, wherein the composition exhibits improved resistance toshear treatment relative to native starch alone.
 2. The method accordingto claim 1 characterized in that the weight ratio of citrus fruit fiberto native starch is between 1:5 and 1:3.6.
 3. The method according toclaim 1 characterized in that the citrus fruit fiber is obtainable fromcitrus fruit selected from the group consisting of oranges, tangerines,limes, lemons, and grapefruit.
 4. The method according to claim 1characterized in that the citrus fruit fiber comprises from 8 to 12%(w/w) proteins.
 5. The method according to claim 1 characterized in thatthe native starch is a waxy starch.
 6. The method according to claim 5characterized in that the native starch is glutinous rice flour.
 7. Themethod according to claim 1, wherein mechanical treatment is applied viaequipment selected from a group consisting of high shear mixers, highpressure valve homogenization, microfluidization, and high powerultrasound.